Sediment penetration by towed, seabed-contacting, fishing gear components.

The penetration of towed fishing gears into the seabed is directly related to contact drag, fuel consumption, habitat alteration and to the depletion of benthic fauna. Hence, is an important parameter in relation to the environmental and ecological impact of towed demersal fishing gears. Here, we use a benthic sledge to tow bottom contacting gear components across soft sediment substrates and make high resolution measurements of their penetration, while the impact is taking place. We demonstrate that penetration increases on softer sediments, with increased pressure forces and with higher aspect ratio, and decreases with faster towing speeds. These results provide a better understanding of the impact of towed demersal fishing gears and will improve assessment methods, increase the accuracy and resolution of ecological indicators and will contribute to the identification of mitigation measures that will lead to the design of low impacting, fuel efficient gears of reduced drag.